Two lateral masses of gray matter connected by the intermediate mass?
That sounds as if it is a brain.
It is the Thalamus.
The thalamus consists of two lateral masses of neural tissue that are joined by a narrow isthmus of neural tissue called the intermediate mass.
Sir Issac Newton proposed theory of gravity. He formulated the relation between the force of gravity and the mass and the distance between the masses. This theory failed to explain as to why there is attraction between the masses and not repulsion. With every attraction you have to have corresponding repulsion. That problem is resolved with the discovery of antimatter. So like attracts like. So matter attracts matter and antimatter attracts antimatter. This fallows that…
Air, like all matter, is attracted to other matter. The bigger the "other matter" the stronger the attraction. Because of this, matter (including air) tends to clump together into masses (planets, stars). This process inevitably leaves gaps in-between these masses that don't contain any matter. Collectively, these airless gaps are referred to as "space" or "the vacuum".